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Multi-Robot Systems with ROS Lesson 6

Multi-Robot Systems with ROS Lesson 6. Teaching Assistant: Roi Yehoshua roiyeho@gmail.com. Agenda. ROS navigation stack with multiple robots Using rviz Sending goals to robots. ROS Navigation Stack. http://wiki.ros.org/navigation

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Multi-Robot Systems with ROS Lesson 6

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  1. Multi-Robot Systems with ROS Lesson 6 Teaching Assistant: RoiYehoshua roiyeho@gmail.com

  2. Agenda • ROS navigation stack with multiple robots • Using rviz • Sending goals to robots (C)2014 Roi Yehoshua

  3. ROS Navigation Stack • http://wiki.ros.org/navigation • The navigation stack handles moving a robot from one position to another position safely (without crashing or getting lost) • It takes in information from odometry and the sensors, and a goal pose and outputs safe velocity commands (C)2014 Roi Yehoshua

  4. ROS Navigation Stack (C)2014 Roi Yehoshua

  5. Navigation Stack Main Components • map_server - offers map data as a ROS Service • gmapping - provides laser-based SLAM (Simultaneous Localization and Mapping) • amcl - a probabilistic localization system • global_planner - implementation of a fast global planner for navigation • local_planner - implementations of the Trajectory Rollout and Dynamic Window approaches to local robot navigation • move_base - links together the global and local planner to accomplish the navigation task  (C)2014 Roi Yehoshua

  6. Navigation Stack Requirements • There are three main hardware requirements: • The navigation stack can only handle a differential drive and holonomic wheeled robots. • A planar laser must be mounted on the mobile base of the robot to create the map and localization • Its performance will be best on robots that are nearly square or circular (C)2014 Roi Yehoshua

  7. Navigation Stack with Multiple Robots • Download the navigation tutorials from git • https://github.com/ros-planning/navigation_tutorials • This will create a navigation_stack package • In the launch directory of the package you will find move_base_multi_robot.launch • This is an example launch file for running the navigation stack with multiple robots in stage • $ cd ~/ros/stacks • $ git clone https://github.com/ros-planning/navigation_tutorials.git (C)2014 Roi Yehoshua

  8. move_base_multi_robot.launch (1) • Remove the first argument in the stage_ros node to make stage’s window visible • Nodes that are common to all robots: • <launch> • <master auto="start"/> • <param name="/use_sim_time" value="true"/> • <node pkg="map_server" type="map_server" name="map_server" args="$(find navigation_stage)/stage_config/maps/willow-full.pgm 0.1" respawn="false" > • <param name="frame_id" value="/map" /> • </node> • <node pkg="stage_ros" type="stageros" name="stageros" args="$(optenv ROS_STAGE_GRAPHICS -g)$(find navigation_stage)/stage_config/worlds/willow-pr2-multi.world" respawn="false"> • <param name="base_watchdog_timeout" value="0.2"/> • </node> (C)2014 Roi Yehoshua

  9. move_base_multi_robot.launch (2) • Nodes for controlling robot 0: • <!-- BEGIN ROBOT 0 --> • <group ns="robot_0"> • <param name="tf_prefix" value="robot_0" /> • <node pkg="move_base" type="move_base" respawn="false" name="move_base_node" output="screen"> • <remap from="map" to="/map" /> • <param name="controller_frequency" value="10.0" /> • <rosparam file="$(find navigation_stage)/move_base_config/costmap_common_params.yaml" command="load" ns="global_costmap" /> • <rosparam file="$(find navigation_stage)/move_base_config/costmap_common_params.yaml" command="load" ns="local_costmap" /> • <rosparam file="$(find navigation_stage)/move_base_config/local_costmap_params.yaml" command="load" /> • <rosparam file="$(find navigation_stage)/move_base_config/global_costmap_params.yaml" command="load" /> • <rosparam file="$(find navigation_stage)/move_base_config/base_local_planner_params.yaml" command="load" /> • </node> (C)2014 Roi Yehoshua

  10. move_base_multi_robot.launch (3) • <node pkg="fake_localization" type="fake_localization" name="fake_localization" respawn="false" output="screen"> • <param name="odom_frame_id" value="robot_0/odom" /> • <param name="base_frame_id" value="robot_0/base_link" /> • </node> • </group> • <!-- END ROBOT 0 --> (C)2014 Roi Yehoshua

  11. move_base_multi_robot.launch (4) • Nodes for controlling robot 1: • <!-- BEGIN ROBOT 1 --> • <group ns="robot_1"> • <param name="tf_prefix" value="robot_1" /> • <node pkg="move_base" type="move_base" respawn="false" name="move_base_node" output="screen"> • <remap from="map" to="/map" /> • <param name="controller_frequency" value="10.0" /> • <rosparam file="$(find navigation_stage)/move_base_config/costmap_common_params.yaml" command="load" ns="global_costmap" /> • <rosparam file="$(find navigation_stage)/move_base_config/costmap_common_params.yaml" command="load" ns="local_costmap" /> • <rosparam file="$(find navigation_stage)/move_base_config/local_costmap_params.yaml" command="load" /> • <rosparam file="$(find navigation_stage)/move_base_config/global_costmap_params.yaml" command="load" /> • <rosparam file="$(find navigation_stage)/move_base_config/base_local_planner_params.yaml" command="load" /> • </node> (C)2014 Roi Yehoshua

  12. move_base_multi_robot.launch (5) • <node pkg="fake_localization" type="fake_localization" name="fake_localization" respawn="false"> • <param name="odom_frame_id" value="robot_1/odom" /> • <param name="base_frame_id" value="robot_1/base_link" /> • </node> • </group> • <!-- END ROBOT 1 --> • <node name="rviz" pkg="rviz" type="rviz" args="-d $(find navigation_stage)/multi_robot.rviz" /> • </launch> (C)2014 Roi Yehoshua

  13. Running the Navigation Stack • To run this launch file type: • $ roslaunchnavigation_stagemove_base_multi_robot.launch (C)2014 Roi Yehoshua

  14. Running the Navigation Stack (C)2014 Roi Yehoshua

  15. rviz (C)2014 Roi Yehoshua

  16. Using rviz with Navigation Stack • rviz is a ROS 3D visualization tool that lets you see the world from a robot's perspective • rviz can help you work with the navigation stack, including: • Displaying all the visualization information that the navigation stack provides, such as the global and local plans and the costmaps • Sending goals to the navigation stack • Setting the initial pose of the robot for a localization system like amcl (C)2014 Roi Yehoshua

  17. Map in Stage and rviz (C)2014 Roi Yehoshua

  18. Map in Stage and rviz • By default the origin of the map is different in Stage and rviz • In Stage the origin is by default at the center of the map while in rviz it is at the lower-left corner • The map’s origin in Stage can be changed by adjusting the floorplan pose in its world file • rviz reads the map from the /map topic that is published by map_server • Its origin can be changed in the map’s yaml file (C)2014 Roi Yehoshua

  19. Map in Stage and rviz • Change the map’s pose in Stage world file so the map’s origin will be adjusted to its origin in rviz • Also change the robots’ positions accordingly • # load an environment bitmap • floorplan • ( • name "willow" • bitmap "../maps/willow-full.pgm" • size [58.4 52.6 0.5] • #pose [ -26.300 29.200 0 90.000 ] • pose [ 29.2 26.2 0 0 ] • ) • # throw in a robot • #pr2( pose [ -21.670 47.120 0 28.166 ] name "pr2_0" color "blue") • #pr2( pose [ -21.670 48.120 0 28.166 ] name "pr2_1" color "green") • #block( pose [ -24.269 48.001 0 180.000 ] color "red") • pr2( pose [ 9.5 14.5 0 28.166 ] name "pr2_0" color "blue") • pr2( pose [ 9.5 15.5 0 28.166 ] name "pr2_1" color "green") • block( pose [ 12.5 15.5 0 180.000 ] color "red") (C)2014 Roi Yehoshua

  20. Map in Stage and rviz (C)2014 Roi Yehoshua

  21. Robot Footprint • To see the robot’s footprint in rviz change the robot footprint topic to: /robot_N/move_base_node/local_costmap/footprint_ layer/footprint_stamped • In our case, the robots have a pentagon-shape • Defined inmove_base_config/costmap_common_params.yaml (C)2014 Roi Yehoshua

  22. Robot Footprint (C)2014 Roi Yehoshua

  23. TF • Add the TF display to watch the TF tree (C)2014 Roi Yehoshua

  24. Sending Goals • The 2D nav goal button allows you to send a goal to the navigation by setting a desired pose for the robot to achieve • By default the goal is published on the topic /move_base_simple/goal • However, when having multiple robots, the topic is /robot_N/move_base_simple/goal  • To change the topic name, first enable the Tool Properties panel via the Panels menu (C)2014 Roi Yehoshua

  25. Sending Goals (C)2014 Roi Yehoshua

  26. Sending Goals • Change the 2D Nav Goal topic to /robot_0/move_base_simple/goal • Click on the 2D Nav Goal button (or press G) and select the map and the goal for the first robot • You can select the x and y position and the end orientation for the robot (C)2014 Roi Yehoshua

  27. Sending Goals (C)2014 Roi Yehoshua

  28. Sending Goals (C)2014 Roi Yehoshua

  29. Collision Avoidance • To avoid the robots from colliding into each other, change the following definition in willow-pr2-multi.world: • define pr2 position • ( • size [0.65 0.65 0.25] • origin [-0.05 0 0 0] • gui_nose 1 • drive "omni” • topurg(pose [ 0.275 0.000 -0.1 0.000 ]) • ) (C)2014 Roi Yehoshua

  30. Using the Navigation Stack • We will now create a node that will make a given robot to move to a specific location on the map • First create a package called navigation_multi that depends on roscpp, rospy, tf, action_lib and move_base_msgs • Build the package by calling catkin_make • Open the package in Eclipse and add a new source file called print_location.cpp • $ cd ~/catkin_ws/src • $ catkin_create_pkgnavigation_multiroscpprospytfactionlibmove_base_msgs (C)2014 Roi Yehoshua

  31. Integrating with move_base • Copy the following directories and files from the navigation_stage package to your package: • Copy the entire directory move_base_config • From the launch directory copy move_base_multi_robot.launch • From stage_config/maps copy willow-full.pgm • From stage_config/worlds copy willow-pr2-multi.world • From the root directory copy multi_robot.rviz (C)2014 Roi Yehoshua

  32. Package Directory Structure (C)2014 Roi Yehoshua

  33. Integrating with move_base • move_base_config files: (C)2014 Roi Yehoshua

  34. Integrating with move_base • Fix move_base.xml to use the correct package: (C)2014 Roi Yehoshua

  35. Integrating with move_base • Fix the package name also in the launch file: (C)2014 Roi Yehoshua

  36. Check Package Configuration • Test that all the configuration is correct by running the launch file: $ roslaunchnavigation_multinavigation_multi.launch (C)2014 Roi Yehoshua

  37. Sending Goals From Code • Open the project file in Eclipse • Under the src subdirectory, create a new file called send_goal.cpp (C)2014 Roi Yehoshua

  38. Using the Navigation Stack • Open the package in Eclipse and add a new source file called send_goal.cpp • Copy the following code into it (C)2014 Roi Yehoshua

  39. send_goal.cpp (1) #include <ros/ros.h> #include <move_base_msgs/MoveBaseAction.h> #include <actionlib/client/simple_action_client.h> #include <tf/transform_datatypes.h> typedefactionlib::SimpleActionClient<move_base_msgs::MoveBaseAction> MoveBaseClient; using namespace std; int main(intargc, char** argv) { if (argc < 2) { ROS_ERROR("You must specify leader robot id."); return -1; } char *robot_id = argv[1]; ros::init(argc, argv, "send_goals"); ros::NodeHandlenh; // Define the goal doublegoal_x = 7.45; doublegoal_y = 18.5; doublegoal_theta = 0; (C)2014 Roi Yehoshua

  40. send_goal.cpp (2) // Create the string "robot_X/move_base" string move_base_str = "/robot_"; move_base_str += robot_id; move_base_str += "/move_base"; // create the action client MoveBaseClient ac(move_base_str, true); // Wait for the action server to become available ROS_INFO("Waiting for the move_base action server"); ac.waitForServer(ros::Duration(5)); ROS_INFO("Connected to move base server"); // Send a goal to move_base move_base_msgs::MoveBaseGoal goal; goal.target_pose.header.frame_id = "map"; goal.target_pose.header.stamp = ros::Time::now(); goal.target_pose.pose.position.x = goal_x; goal.target_pose.pose.position.y = goal_y; (C)2014 Roi Yehoshua

  41. send_goal.cpp (3) // Convert the Euler angle to quaternion double radians = goal_theta * (M_PI/180); tf::Quaternion quaternion; quaternion = tf::createQuaternionFromYaw(radians); geometry_msgs::Quaternion qMsg; tf::quaternionTFToMsg(quaternion, qMsg); goal.target_pose.pose.orientation = qMsg; ROS_INFO("Sending goal to robot no. %s: x = %f, y = %f, theta = %f", robot_id, goal_x, goal_y, goal_theta); ac.sendGoal(goal); // Wait for the action to return ac.waitForResult(); if (ac.getState() == actionlib::SimpleClientGoalState::SUCCEEDED) ROS_INFO("You have reached the goal!"); else ROS_INFO("The base failed for some reason"); return 0; } (C)2014 Roi Yehoshua

  42. Compiling the Node • Change the following lines in CMakeLists.txt: • Then call catkin_make • For example, to send a goal to robot no.1 type: • cmake_minimum_required(VERSION 2.8.3) • project(tf_multi) • … • ## Declare a cpp executable • add_executable(send_goalsrc/send_goal.cpp) • … • ## Specify libraries to link a library or executable target against • target_link_libraries(send_goal ${catkin_LIBRARIES}) • $ rosrunnavigation_multisend_goal 1 (C)2014 Roi Yehoshua

  43. Running send_goal node (C)2014 Roi Yehoshua

  44. Running send_goal node • Initial position: (C)2014 Roi Yehoshua

  45. Running send_goal node • In the middle of the path: (C)2014 Roi Yehoshua

  46. Running send_goal node • Final position: (C)2014 Roi Yehoshua

  47. send_goal Parameters • Now let us make the desired pose of the robot configurable in a launch file, so we can send different goals to the robots from the terminal • You can define parameters for a node by using the <param> tag in the ROS launch file • Create the following send_goals.launch file (C)2014 Roi Yehoshua

  48. send_goal Parameters <launch> <!-- BEGIN ROBOT 0 --> <group ns="robot_0"> <param name="goal_x" value="6.32" /> <param name="goal_y" value="17.67" /> <param name="goal_theta" value="0" /> <node pkg="navigation_multi" type="send_goal" respawn="false" name="send_goal" output="screen" args="0"/> </group> <!-- END ROBOT 0 --> <!-- BEGIN ROBOT 1 --> <group ns="robot_1"> <param name="goal_x" value="10.12" /> <param name="goal_y" value="12.97" /> <param name="goal_theta" value="45" /> <node pkg="navigation_multi" type="send_goal" respawn="false" name="send_goal" output="screen" args="1"/> </group> <!-- END ROBOT 1 --> </launch> (C)2014 Roi Yehoshua

  49. send_goal Parameters • Now roslaunchsend_goal.launch: (C)2014 Roi Yehoshua

  50. send_goal Parameters (C)2014 RoiYehoshua

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